I am working on a battery PSU for my gainclone. It will have two 12V SLAs in series for each of 4 rails. I would, for obvious reasons, like to avoid having to use a charger for each battery or even rail.

First, can I charge two in series as I would one without determent to either of the batteries? Will one battery get a smaller share of the charging current? Does having one battery draw current through another battery degrade the latter? If there is a reason to charge them separately then should a simple resistor divider between batteries and charger suffice? If this isn't the case am I not right in thinking that I should use 24v with varying amperage (as necessitated by the type of charging being done) but with the resistor/divider I should use 12v/with twice the previous amperage?

For that matter, can I use a resistor divider after the batteries so that I can split 4 batteries charging in series into 2 24v ?

Originally posted by LeoBloom ........Will one battery get a smaller share of the charging current? Does having one battery draw current through another battery degrade the latter? If there is a reason to charge them separately then should a simple resistor divider between batteries and charger suffice? .............

You should charge each battery separately for the reasons you mention. I've made a kind of multiplexer, that will charge a series of SLA's one by one in a cyclus of 4x15 minutes appr. You can use one charger to charge 4 batteries this way - see my thread and look for post #18.